The optimal operative protocol to accomplish CO2-EVAR resulting from a prospective interventional multicenter study.

OBJECTIVES: Carbon dioxide (CO2) angiography for endovascular aortic repair (CO2-EVAR) is used to treat abdominal aortic aneurysms (AAAs), especially in patients with chronic kidney disease or allergy to iodinated contrast medium (ICM). However, some technical issues regarding the visualization of the lowest renal artery (LoRA) and the best quality image through angiographies performed from pigtail or introducer sheath are still unsolved. The aim of this study was to analyze different steps of CO2-EVAR to create an operative standardized protocol. METHODS: Patients undergoing CO2-EVAR were prospectively enrolled in five European centers from 2019 to 2021. CO2-EVAR was performed using an automated injector (pressure, 600 mmHg; volume, 100 cc); a small amount of ICM was injected in case of difficulty in LoRA visualization. LoRA visualization and image quality (1 = low, 2 = sufficient, 3 = good, 4 = excellent) were analyzed at different procedure steps: preoperative CO2 angiography from pigtail and femoral introducer sheath (first step), angiographies from pigtail at 0%, 50%, and 100% of proximal main body deployment (second step), contralateral hypogastric artery (CHA) visualization with CO2 injection from femoral introducer sheath (third step), and completion angiogram from pigtail and femoral introducer sheath (fourth step). Intraoperative and postoperative CO2-related adverse events were also evaluated. χ2 and Wilcoxon tests were used for statistical analysis. RESULTS: In the considered period, 65 patients undergoing CO2-EVAR were enrolled (55/65 [84.5%] male; median age, 75 years [interquartile range (IQR), 11.5 years]). The median ICM injected was 17 cc (IQR, 51 cc); 19 (29.2%) of 65 procedures were performed with 0 cc ICM. Fifty-five (84.2%) of 65 patients underwent general anesthesia. In the first step, median image quality was significantly higher with CO2 injected from femoral introducer (pigtail, 2 [IQR, 3] vs introducer, 3 [IQR, 3]; P = .008). In the second step, LoRA was more frequently detected at 50% (93% vs 73.2%; P = .002) and 100% (94.1% vs 78.4%; P = .01) of proximal main body deployment compared with first angiography from pigtail; similarly, image quality was significantly higher at 50% (3 [IQR, 3] vs 2 [IQR, 3]; P ≤ .001) and 100% (4 [IQR, 3] vs 2 [IQR, 3]; P = .001) of proximal main body deployment. CHA was detected in 93% cases (third step). The mean image quality was significantly higher when final angiogram (fourth step) was performed from introducer (pigtail, 2.6 ± 1.1 vs introducer, 3.1 ± 0.9; P ≤ .001). The intraoperative (7.7%) and postoperative (12.5%) adverse events (pain, vomiting, diarrhea) were all transient and clinically mild. CONCLUSIONS: Preimplant CO2 angiography should be performed from femoral introducer sheath. Gas flow impediment created by proximal main body deployment can improve image quality and LoRA visualization with CO2. CHA can be satisfactorily visualized with CO2 alone. Completion CO2 angiogram should be performed from femoral introducer sheath. This operative protocol allows performance of CO2-EVAR with 0 cc or minimal ICM, with a low rate of mild temporary complications.

Embolization for Type Ia Endoleak after EVAR for Abdominal Aortic Aneurysms: A Systematic Review of the Literature.

(1) Successful endovascular repair for abdominal aortic aneurysms is based on the complete exclusion of the aneurysm sac from the systemic circulation. Type Ia endoleak (ELIA) is defined as the persistent perfusion of the aneurysm sac due to incomplete proximal sealing between aorta and endograft, with a consequent risk of rupture and death. Endoleak embolization has been sporadically reported as a viable treatment for ELIA. (2) A systematic literature search in PubMed of all publications in English about ELIA embolization was performed until February 2022. Research methods and reporting were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Data regarding patient numbers, technical success (endoleak absence at control angiography), reinterventions, clinical and imaging follow-up, and outcomes were collected and examined by two independent authors. (3) Twenty-one papers (12 original articles, 9 case reports) reported on 126 patients (age range 58-96 years) undergoing ELIA embolization 0-139 months after the index procedure. Indication for embolization was most often founded on unfavorable anatomy and patient comorbidities. Embolic agents used include liquid embolic agents, coils, plugs and combinations thereof. Technical success in this highly selected cohort ranged from 67-100%; the postprocedural complication rate within 30 days was 0-24%. ELIA recurrence was reported as 0-42.8%, with a secondary ELIA-embolization-intervention success rate of 50-100%. At a follow-up at 0-68 months, freedom from sac enlargement amounted to 76-100%, freedom from ELIA to 66.7-100%. (4) Specific literature about ELIA embolization is scant. ELIA embolization is a valuable bailout strategy for no-option patients; the immediate technical success rate is high and midterm and long-term outcomes are acceptable.